Safety device for escalators



Dec. 14 1926. 1,616,428

w. A. DALY ET AL SAFETY DEVICE FOR ESCALATORS Filed Augist 30, 192,1 2Sheets-Sheet l A75 wuemtow Dec. 14 1926. 1,610,428

w. A. DALY ET AL SAFETY DEVICE FOR ESCALATORS Filed August 30. 1922 2Sheets-Sheet 2 WEI A2 jL/l Patented Dec, 14, 1926.

UNITED STATES A 1,610,428 PATENT OFFICE.

WILIERIIiD A. DALY, OF YOINKERS, AND SAMUEL G. MARGLES, OE BROOKLYN, NEWYORK, ASSIG'NORS TO OTIS ELEVATORCOMPANY, OF JERSEY CITY, NEW JERSEY, A

CORPORATION OF NEW JERSEY.

SAFETY DEVICE FOR ESCALATORS.

Application filed August Our invention relates particularly to ceritainimprovements in escalators which employ endless chains to which thesteps, cleats or tread sections of the escalator are attached and movethem along on or in ways or tracks designed for that purpose. It is heldin the practical arf'that it is important to provide escalators with asuitable emergency safety device which in case of the breaking of thechains will effect and insure the safe and proper stopping of theescalator, preferably substantially the whole escalator and virtuallyimmediately or actually at once upon the breaking of a chain. In thattype of escalator or inclined conveyer in which two chains are employed,and to which the moving steps areattached, the chains are usually placedapart from each other a considerable distance, depending upon the widthof the steps measured from end toend. In the type of escalator in whichour invention is more especially designed to be used the two chains arespaced apart from each other a-pproximately the width of the steps orcleats,

and are attached to the upper front carriers of each step, and carrywheels upon which =ne steps and chains roll along. In considering thesafety features to be provided with such type of escalator. it isimportant that a suitable safety device shall be provided. which willact to cut or shut off the power from the driving machine and applythey" brake to the escalator and cause the immei. =diate stopping of thewhole escalator, should either of the chainsbreak in two from any cause.Should one chain be broken, and the other chain remain intact, it isclear that the broken'chain will allow that side of all of the stepsfollowing to sag back thereby throwing great stress on the unbrokenchain," and possibly, if not probably, causing the steps to assume askewed position or conditioir'and jam in the guides in the escalatorwith resulting damage to the structure and possible injury to thepassengers. Any device to afford protection in such a case ofaccidentand which will act to cause immediate stopping of the escalator musthave an actuating mechanism which will be instantly affected tofunctionby any change in speed. and consequently-the relative positions,of the two chains; in other words, such an actuating device must beinstantly affected by any difference in speed of the two chains; in

, 1922. Serial No. 585,955.

brief, it must possess, among other qualities, the attribute of adifferential device. It is the object of our invention to provide asafety device possessing the characteristics tached to chains, with ourinvention combined with the escalator.

Figure 2 is a more or less detail and assembly illustration of oursafety device, taken on theline 2-2 of Figure 3, with a switch showntherein in elevation, in and with an escalator.

'Figure 8 is an end view in assembly of type, having steps 1, or cleats,or other form pf tread or carrying sections, designed to constitute amovable tread platform or surface adapted to be inclined fand connecttwo different floor levels (not shown) The steps are attached at-theopposite sides of their front ends to two endless driving chains, 2,running parallel to each other at the sides of the escalator,andcarrying wheels, 3, upon which the straps and chains move along.

The track rails, 4, are suitably arranged or laid in 'a well knownmanner to constitute the horizontal and incline runs for and between thefloor landings of the escalator, the rails constituting an upper andlower run for the steps. The two endless chains, 2, are arranged on acenter line coinciding with the center line of two sprocket Wheels, 5,one sprocket wheel only being seen on the figures, The driving chains,2, in the present illustrations comprise a series of links, 6, ivotallyconnected to the front wheel axles, adapted to form endless chains. Thechains pass around the sprocket wheels, 5, and may be driven by anysuitable power, an electric shaft. 29 for both sprocket. wheels.

motor, 8, for example, as, illustrated in Figure 1.

Coming now to a more particular description of our safety deviceinvention, in the forms illustrated herein, it may consist. as shown inFigures 2 and 3,01 two thin idling sprocket wheels, 9, with'teeth, '10,to fit the escalator chains, 2; each idling sprocket, 9, is driven byits escalator step chain. 2. In the normal operation of the escalatorthe two chains travel exactly at one and the same speed, therefore thetwo idler sprockets, 9, will rotate at one and the same speed with eachother. If, however, any difference in speed of the two chains occurs.the two idler sprockets will be rotated at different speeds from eachother. One idler sprocket 9 is attached to a curved arm 11 on a shaft 24common to both sprocket wheels and the arm is so arranged that unlessequal speedof rotation of the two sprockets is maintained the dilferencein their relative speeds of rotation will cause the arm 11 by a roller12 afiixed thereto to move out of a recess 13, on another suitablemember 14 and move the said member in the operation. The member 14 inturn moves a bolt 15 held by an arm 16 hinged at 17 to'jan electricalswitch 18 to trip a trigger 19 of the switch, breaking the electricalconnection between contacts 20 of the switch. To accomplish this thetrigger 19 is pivotally mounted at one end on pin 51 and provided witha. notch 52 at the end of a projection 53. Arm 16 is provided with p alatch 54 which. in the normal position as shown in Fig. 2, engages withnotch. 52.

Upon movement of-bolt 15 and consequently arm 16 about hinge point 17,latch 54 is movedou't of notch 52, thereby permitting trigger 19 to dropand pivotabout pin 51 to open contacts 20. The action of the member 11is against springs 21 and bolts 22 in the member and fastened to a Vgrooved drum 23 pinned to the shaft of the safety device. The contacts20 in opening are adapted to break the circuit to a winding- 25 of amotor switch B shown in Figure 1 and. the switch in becomingdeen'ergized will, by its then open contacts 26, open the circuit to theescalator driving motor 8 and stop it and the escalator.

Our differential safety device. so to speak. is shown in another form inFigures 4 and 5. The two thin idling sprocket wheels 9 in Figure 4anddescrihed in connection with Figures 2 and 3 have teeth to fit theescalator chain 2, and each is driven by its escalator step chain 2. Inthe present figures a hub 2T to which one sprocket wheel is' attached iskeyed by a. key 28 to a common The other sprocket wheel 9 is fastened toa hub 30 that is loose on the shaft 29. The hub 30 has slots 31 thereinas seen in Figure 5.

A member 32, also keyed to the shaft 29 by akey 33, has fingers 34formed thereon and is held to the hub by the fingers engaging; the hubsfull parts. 'Since the member 32 and one sprocket wheel 9 by its-hub 27is keyed to the shaft 29 of the device they will at all times rotate atthe same speed, and also the other sprocket wheel 9 under normalconditions. Should the speed of the sprocketwheel 9 on the hub 30 becomedifferent than that of the other sprocket wheel 9 and member 32, thefingers 34 on the memher 32 will move over the surface of the full partsof the hub between its slots 31 until the slots are reached at whichtime the fingers will slip through the slots by the action of a spring35 between the hub and member 32 and cause the said member to move abolt 36 held by an arm 37 hinged at 38 to an electrical switch 39, andcause the motor 8 and the escalator to be stopped as told before withFigures2 and 3.

Our safety device invention is also for stopping an escalator of theascending type immediately upon it being caused to reverse to adirection of travel that is other than its normal direction. With theabove object in view the device comprises a pair of arms 40, each havingan inverted V-shaped hearins: surface and held together and to the Vgroove drum 23 by a pair of rods 41. The rods have springs 42 thereon tokeep the arms to the drum to take up the wear since the drum rotateswith the shaft 24 to which I it is pinned by a pin 43 and with thesprocket wheels 9 when they are operated by the escalator. One arm 40has a finger 44 formed thereon which holds a trigger 45 of an electricalswitch 46 and the trigger holds a pair of contacts 47 of the switch inelectrical connection with each other. A projection- 48 also formed onthe same arm 40 is adapted to abut against a bolt 49 held by a plate 50fastened to the escalator frame work and which holds both. arms 40 fromturning, Should the escalator be cau ed to reverse to a down directionof travel the finger 44 will leave the trigger 45 which will drop downand break the electrical connection between the contacts 47 of theswitch and cause the escalator driving motor 8 to be stopped. As shownin Figure 1 the switch 46 is in common with the other switch 18 of thedevice, each in being opened causing the escalator motor to be stopped.

One skilled in the art may make obvious vice comprising the combinationof members adapted upon the breaking of a chain to engage saidchainsmeans to control the operating power for the chains, adapted to beoperated by said engaged members to effect the interruption of the powerfor the chains.

3. In the art of conveyers having transporting chains, adapted to beoperated by an electric motor, a safety device comprising thecombination of members one ofwhich is adapted upon the breaking of atransporting chain to be operated by an 111- tact chain, a switchadapted to be operated by said member upon the breaking of a chain andeffect the stopping of the motor.

4. In an endless conveyer having transporting chains adapted to beoperated by an electric motor, a safety device for stopping the motor incase of the breaking of a transporting chain, comprising the combinationof movable members adapted in the normal operation of the conveyer tobenmoved together by said-chains and upon the breaking of a chain to bedifferentially moved. a switch adapted to be operated upon thedifferential movement of said members and interrupt the power tothen'iotor.

5. In the art of power driven mclinedcon-,

veyers of the escalator type of endless stepforimn'g sections, thecombination of the step-carrying chains, and a safety device foreffecting the stopping of the escalator in case of the breaking of achain. said device comprising wheels adapted in the normal operation ofthe escalator to rotate at the same speed, but upon the breaking of achain to rotate at a differential speed, and ower cut-out means adaptedto be operatec as a consequence of said difference in speed, to

cause the interruption of the driving-power.

for the escalator;

6. In the'art of emergency safety devices for escalators, havingsteps-carrying chains, adapted to be driven by an electric powerapparatus, a safety device comprised of Wheels driven by said chain andadapted upon the breaking of a chain to be rotated at a differentialspeed, and amember controlling the power apparatus for the es calatoradapted to operate and interrupt the operation of said power apparatus,as a consequence of said differential speed, thereby allowing theescalator to stop.

7 In the art of emergency safety devices for escalators, havingsteps-carrying chains, adapted to be driven by an electric motor, anelectric contact to control said motor, a safety device comprised ofmembers driven upon the breaking of a chain at a differential speed,arms to whiclrsaid members are attached, a normally locked member,adapted to be released as a consequence of said differential speed, andthereby open Said contact and allow the escalator to stop.

8. In an escalator having a driving chain and motive means for normallydriving said chain in. one direction, a controlling device having an onposition and an off position, said device, when in its on position,permitting the supply of power to said motive means, and, upon beingreleased to off position, causing the discontinuance of the supply ofpower to said motive means, a member driven by said chain, and mechanismfrictionally engaging said member to maintain said controlling device'inits on position when the chain is being driven in said one 'direction,saidmechanism being operated by said member to release said controllingdevice to its off position upon a reversal of the direction of'motion ofsaid chain, regardless of the cause of the reversal.

9. In the art of emergency safety devices for inclined ascendingconveyers, adapted to be driven by an electric motor, a closed electricswitch to control said motor, a safety device comprising a rotatabledrum, pressure members on'the drum adapted to turn when the conveyer isaccidentally reversed, one of the said members having a finger adaptedto open said switch as a consequence of the reversal of the conveyer andallow the conveyer to stop.

In testimony whereof, we have signed our names to this specification.

WILFRID A. DALY. SAMUEL e. MA'RGLES.

